1. Field of the Invention
This invention relates in general to electrical test apparatus, and in particular to apparatus for testing the energy level across the electrical contacts in an electrical detonator circuit used to fire a pyrotechnic cartridge in a weapons system such as those used on military aircraft.
2. Description of the Prior Art
Previously, apparatus and systems have been developed for testing detonator circuits in weapons systems to detect spurious electrical energy when the detonator circuit is intentionally energized, or a selected threshold quantity of electrical energy when the system is de-energized.
As explained in U.S. Pat. No. 3,505,635, pyrotechnic cartridges are now extensively utilized in aircraft for ejecting bombs or other weapons. These cartridges are releasably connected with electrical circuitry, which when energized, detonates the cartridge, thus emitting a high-pressure gas which may, for example, release a latching device and immediately thereafter eject a bomb. Such devices have proven dangerous during the arming of aircraft previous to missions. Premature ejection of a bomb occurs upon inserting one of the cartridges into a well in which the detonator circuit has been accidentally or inadvertently energized. Accordingly, it is essential that the detonator circuit of such devices be tested prior to arming the weapons system for the presence or level of electrical energy.
A satisfactory test probe for insertion into a pyrotechnic cartridge well or breech cap is disclosed in U.S. Pat. No. 3,505,635. In such devices, the test indicators which detect the quantity of electrical energy across the electrical contacts in a pyrotechnic cartridge well or breech cap are located on the exterior of the test probe, usually in a console electrically connected with the test probe. Commonly, such console contains electrical circuits and power sources, which themselves are capable of malfunction, with the result that it is sometimes difficult to know with certainty whether the pyrotechnic detonator circuit or the test circuit is defective.
It is accordingly, the general object of this invention to provide a small, protable and rugged test instrument requiring no batteries or supplemental power supply for testing various aircraft weapons release firing signals with essentially fail-safe reliability.
Another object of the invention is to provide a current potential indicator, especially suitable for weapons systems testing, that utilize a test probe, an electrical minimum event indicator to detect a minimum amount of electrical energy, and an electrical threshold indicator for sensing a selected quantity of electrical energy above said minimum.
Another object of the invention is to provide in a weapons test system a current potential indicator including a minimum event indicator and a threshold indicator combined with a constant current source for greater accuracy in sensing selected quantities of electrical energy, such apparatus being self-contained, without need for attachment to a separate test console.
Another object of the invention is to provide a current potential indicator for use in weapons systems including a minimum event indicator and a threshold indicator, as well as resistance means that is variable to enable selection of the quantity of energy that activates the threshold indicator.
Another object of the invention is to provide a current potential indicator, especially suitable for weapons systems testing, including load disconnect means for disconnecting the circuit after a selected interval of electrical energy application.